feat: Add solution for LeetCode problem 70

Author: WhiteHyun

climbing-stairs/WhiteHyun.swift

@@ -0,0 +1,19 @@
+//  
+//  70. Climbing Stairs
+//  https://leetcode.com/problems/climbing-stairs/description/
+//  Dale-Study
+//  
+//  Created by WhiteHyun on 2024/05/12.
+//  
+
+final class Solution {
+  func climbStairs(_ n: Int) -> Int {
+    var dp: [Int] = .init(repeating: 0, count: 45)
+    dp[0] = 1
+    dp[1] = 2
+    for i in 2 ..< 45 {
+      dp[i] = dp[i - 1] + dp[i - 2]
+    }
+    return dp[n - 1]
+  }
+}